Earth boring apparatus



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ATTO/P/VE V EARTH BORING AIPARATUS 3 Sheets-Sheet 2 Filed June 19, 1964 INVENTOR W////0/77 A? Gavrefz 7 d 3 3 y y .111? B EARTH BORING APPARA TUE 3 Sheets$heet Filed June 19, 1964 W/U/am H. Garre/f INVENTOR United States Patent 3,320,004 EARTH BORING APPARATUS William R. Garrett, Midiand, Tex., assignor to Drilco Oil Tool, Inc., Midland, Tex, a corporation of Texas Filed June 19, 1964, Ser. No. 376,435 9 Claims. (Cl. 308-4) This invention pertains to apparatus useful in earth boring, e.g. in drilling an oilwell by the rotary method. In several types of such apparatus use is made of an elastomeric sleeve disposed around a mandrel arranged for relative rotation or translation or both. Debris of any kind lodging between the mandrel and sleeve is apt to cause undue wear on the mandrel or sleeve or both. The object of this invention is to prevent such lodgement. For purposes of illustration the invention will be described in detail as embodied in a stabilizer, but it is to be understood that the invention is applicable to other types of apparatus embodying a mandrel and sleeve with bearing means therebetween, e.g. the bearings of a hydraulic drill collar. Stabilizers representative of the type herein referred to are shown in US. Patents 2,715,553Lane; 3,063,759Moore et al. issued Nov. 13, 1962, and a hydraulic drill collar is disclosed in US. Patent 3,088,- 532Kellner, issued May 7, 1963.

Briefly, the invention contemplates detrius exclusion means provided by making the fit between the mandrel and the upper part of the sleeve closer than the fit at the bearing means therebelow, so that anything passing through the close fit of the detritus exclusion means at the top will fall out below through the bearing means. Four ways of accomplishing this result will be described:

1) The provision of one or more annular lips at the inner periphery of the sleeve at the upper end thereof, the lips making a wiping contact with the mandrel. This is the preferred embodiment and has the further advantage that the lips not only provide a means to exclude the larger detritus too large to fall through the bearing means but provide a long wearing seal to prevent in large measure the entrance of any debris into the annulus between sleeve and mandrel.

(2) In the case of an interiorly fluted sleeve, the flutes can terminate close to the top of the sleeve. This has the advantage of being a rugged structure not easily damaged and long wearing and at the same time economical to manufacture. The unfluted area at the top of the sleeve forms a close fitting band functioning as a detritus excluding means.

(3) As a variation of the second manner of accomplishing the invention, the internal flutes may be continued all the way to the top of the sleeve but may be shallower at the top than in the major portion of the sleeve therebelow. This has the advantage of facilitating fluid passage through the bearing means between sleeve and mandrel, yet the shallow fluted band serves as detritus exclusion means to protect the bearing means therebelow.

(4) An unfluted sleeve may simply have a detritus exclusion means formed by a band at the top of a smaller inner diameter than throughout the remainder of the sleeve therebelow forming the bearing means.

The elastomeric sleeve should be soft enough at the upper end, where it makes a tight fit, such that it will wear well, the sleeve flexing away from and over obstacles instead of being cut and torn thereby. In fact this is a desirable property of the whole sleeve. A durometer hardness between 35 and 95 on the Shore A scale is suitable.

For a detailed description of preferred embodiments of the invention reference will now be made to the accompanying drawings wherein,

FIGURE 1 is an elevation showing a stabilizer, including mandrel and sleeve, in which the invention may be embodied;

FIGURE 2 is a transverse section taken at the plane indicated at 22 in FIGURE 1;

FIGURE 3 is a fragmentary vertical section through the bottom part of the stabilizer sleeve shown in FIG- URES 1 and 2.

FIGURE 4 is a fragmentary vertical section through the top part of the stabilizer sleeve shown in FIGURES l, 2, and 3, illustrating the preferred embodiment of the invention;

FIGURE 5 is an enlarged fragmentary vertical section through the upper part of the stabilizer sleeve and mandrel shown in FIGURES l, 2, 3 and 4;

FIGURES 6 and 7 are fragmentary vertical sections through the upper parts of stabilizer sleeves embodying modified forms of the invention; and

FIGURES 8 and9 are fragmentary vertical sections through the top and bottom parts of a stabilizer sleeve embodying a further modified form of the invention.

Referring now to FIGURES 1 and 2 there is shown a tubular mandrel 11 having an enlarged lower end 12 forming an upwardly facing shoulder 13. Clutch jaws 14 are formed in shoulder 13. The enlarged end 12 is provided with threaded pin means, not shown, for making connection with a portion of a drill string therebelow. The upper end of the mandrel 11 is provided with a threaded socket 15.

A tubular sub 29 is provided with a threaded pin 21 engaged with socket 15. The upper end of sub 20 is enlarged at 22 forming a downwardly facing shoulder 23. The upper end of sub 20 is provided with threaded box means, not shown, for making connection with the upper part of a drill string.

Rotatably and axially slidably disposed on mandrel 11 is a sleeve 30. Shoulder 13 provides means preventing the sleeve from moving axially down on mandrel 11 past shoulder 13. The sleeve 30 is made of an elastomeric material such as natural material or synthetic rubber suitably compounded and vulcanized and having a durometer hardness on the Shore A scale in the range 35-95. Referring now also to FIGURES 3 and 4, the elastomeric material is preferably reinforced with a cylindrical steel tube 31 to which the elastomer is bonded. Clutch jaws 32 are formed in the lower end of tube 31, buried in the sleeve. The function of this clutch is set forth in the above referred to Moore et a]. and Lane patents. To facilitate flow of the elastomer from the inside of the tube to the outside during molding, the tube is preferably perforated. At the outer periphery of the sleeve are a plurality of longitudinal ribs 33 spaced apart circumferentially therearound, leaving longitudinally extending spaces therebetween providing fluid passages.

The inner periphery of sleeve 39 has a plurality of longitudinal flutes 34 formed therein at circumferentially spaced apart positions, extending upwardly from the lower end of the sleeve to near the upper end thereof. The flutes 34; terminate at 35 about three inches below the upper end 36 of the stabilizer. (The drawings are to scale.) Adjacent the upper end of sleeve 30 there are a plurality e.g. three, annular lips 37. In their relaxed position, as shown in FIGURE 4, the lips have horizontal upper faces 38 and conically tapered, inwardly upwardly converging lower faces 39.

As shown in FIGURE 5, lips 37 make an interference fit with the outer periphery 40 of mandrel 11, and are flexed upwardly when assembled with the mandrel making a wiping engagement and sealing with the mandrel.

It will be apparent that lips 37 will tend to prevent debris from entering the annulus 41 between the sleeve 30 and mandrel 11 and that any such debris which gets past lips 37 will be small enough to drop clear through the annulus out of the way. If the mandrel 11 is undersize due to wear, the lips 37 will flex downwardly and still maintain contact with the mandrel. If the mandrel 11 is so undersize that even in the fully relaxed position shown in FIGURE 4 the lips 37 do not make contact with the mandrel all around it, nevertheless the gap between the lips and mandrel will be much smaller in radial extent than the annulus 41, so that any debris passing between the lips and the mandrel will fall clear through the annulus. The life of the stabilizer, especially the sleeve portion thereof, is thereby considerably prolonged.

The unfluted portion 44 of the stabilizer sleeve, just below the lips 37, is desirable to prevent fluid flowing in the flutes 34 from undercutting the lips.

Referring now to FIGURE 6, 7, 8, and 9, there are shown three modified forms of the invention. The modifications are entirely in the sleeve, the mandrel being the same as in the first embodiment. The sleeve in each case is also generally the same as in the preferred embodiment just described, and parts remaining unchanged will be given the same reference numbers as in FIGURES 1-5, except that the numbers will be increased by 100, 200, and 300 respectively. It will therefore be unnecessary to redescribe these like parts.

Referring now to FIGURE 6, the construction is the same as that of FIGURE 7 except that the lips 37 are omitted leaving a smooth band 145. Band 145 is sized to make a close fit with an unworn mandrel.

In FIGURE 7, the flutes 234 continue on to the upper end 236 of the sleeve, but are of less depth at the upper part of the sleeve, forming shoulders 250 at the juncture of the shallow and deep portions of the flutes. There is no close fit between mandrel and sleeve in this embodiment, reliance being placed on the upflow of fluid in the mandrel-sleeve annulus to keep out most of the debris. Since the flutes extend all the way to the top of the sleeve, the largest openings between sleeve and mandrel are at the tops of the flutes. However, the openings at the tops of the flutes are smaller than the spaces between mandrel and flutes below the upper end of the sleeve so that debris entering the tops of the flutes will fall clear through as soon as it gets to the shoulder 250.

In FIGURES 8 and 9, the stabilizer sleeve 330 is unfluted on its inner periphery. Adjacent the upper end 336 of the sleeve there is a band 345 of smaller diameter than the portion 346 therebelow, forming a downwardly, inwardly facing shoulder 346 therebetween. The portion 345 is sized to make a close fit with an unworn mandrel, similar to band 145 in the FIGURE 6 embodiment.

A further modification that should be mentioned comprises a stabilizer sleeve exactly the same as that shown in FIGURE 4 except that there is only one lip 37, preferably the uppermost, the other two lips 37 being omitted. This has the advantage that debris cannot be trapped between the multiple lips 37 as is sometimes possible in the FIGURE 4 embodiment. This single lip embodiment is best suited for situations where wear adjacent the upper end of the sleeve, e.g., due to the sleeve end rubbing against the shoulder 23 (see FIGURE 1), is not expected to be large. Since the sleeve of this embodiment would be otherwise identical with that shown in FIGURE 4, a separate drawing thereof has not been provided.

While a preferred embodiment of the invention and three modifications thereof have been shown and described, other modifications can be made by one skilled in the art without departing from the spirit of the invention.

That being claimed is:

1. Apparatus for use in earth boring including in combination with a tubular steel mandrel having an upper end and a lower end and having a sleeve coaxially mounted thereon and stop means at the lower end of the mandrel to prevent downward movement of the sleeve relative to the mandrel beyond said stop means, the inner surface of the sleeve having an elastomeric portion, the outer surface of the mandrel and said elastomeric portion of the inner surface of the sleeve providing cooperating steel and elastomer bearing means constraining the relative motion of the mandrel and sleeve substantially to sliding of the elastomeric portion of the inner surface of the sleeve upon the steel outer surface of the mandrel, the improvement comprising elastomeric detritus exclusion means on the inner surface of the sleeve adjacent the upper end of the elastomeric portion thereof cooperating with said mandrel to exclude detritus of larger size than will pass between said cooperating bearing means, said detritus exclusion means and mandrel making a closer fit than said cooperating bearing means extending therebelow from said upper end through the mid portion of said elastomeric portion to the lower end thereof,

whereby detritus that can enter between the sleeve and mandrel at the upper end of the sleeve past said elastomeric exclusion means will be of a size that can fall through the clearance space between said cooperating steel and elastomer bearing means at the outer surface of the mandrel and inner surface of the sleeve without spoiling the sliding fit therebetween.

2. Combination according to claim 1 wherein the sleeve is rotatably mounted on the mandrel by said cooperating bearing means comprising said outer surface of the mandrel and said elastomeric portion at the inner surface of the sleeve, said elastomeric portion being provided with flutes extending longitudinally of the inner surface of the sleeve, said flutes extending from the lower end of said elastomeric portion upwardly past the mid portion of the elastomeric portion that lies half-way between the upper and lower ends thereof, said flutes terminating below the upper end of the elastomeric portion leaving an unfluted band adjacent the upper end of the sleeve, said unfluted band forming said detritus exclusion means, said flutes providing relief of the fit between the mandrel and the elastomeric portion of the sleeve whereby detritus passing said unfluted band can fall through said flutes out of said cooperating bearing means provided by said mandrel and elastomeric portion.

3. Combination according to claim 1 wherein said detritus exclusion means includes annular lip means projecting inwardly toward the mandrel beyond the part of said elastomeric portion below said detritus exclusion means.

4. Combination according to claim 3 wherein said annular lip means makes an interference fit with the mandrel making a seal to exclude substantially all detritus from said bearing means so long as said mandrel remains full size and when the mandrel is worn down excluding detritus of a size too large to fall through said cooperating bearing means.

5. Combination according to claim 4 wherein said annular lip means comprises a plurality of annular lips spaced apart longitudinally of the sleeve, each lip having an upper surface perpendicular to the sleeve axis and a coaxial, conical, upwardly converging lower surface.

6. Combination according to claim 1 wherein said elastomeric detritus exclusion means and said elastomeric portion at the inner surface of said sleeve both have smooth cylindrical inner peripheries, the inner diameter of said detritus exclusion means :being smaller than the inner diameter of the bearing means provided by said elastomeric portion of the inner surface of said sleeve. 7. A drill string stabilizer for use in the rotary system of earth boring including in combination with a tubular steel mandrel having an upper end and a lower end and a sleeve coaxially mounted thereon and stop means at the lower end of the mandrel preventing downward travel of the sleeve past said stop means, the outer periphery of said sleeve being provided with a plurality of longitudinally extending ribs circumferentially spaced apart, the inner periphery of said sleeve being provided with an elastomeric portion, a lower part of said elastomeric portion providing elastomeric bearing means cooperating with said steel mandrel to provide for relative rotation of the sleeve and mandrel, at least said lower part of said elastomeric portion being fluted longitudinally thereof,

the improvement comprising detritus exclusion means formed by an upper part of said elastomeric portion of the inner periphery of said sleeve, said detritus exclusion means making with said mandrel a fit close enough to exclude debris too large to fall through the flutes in said elastomeric bearing means, said upper part of said elastomeric portion being fluted but the flutes in said upper part being of less depth than the flutes in said lower part.

8. Combination according to claim 1 wherein the outer periphery of the sleeve is provided with a plurality of longitudinally extending ribs circumferentially spaced apart, and

the sleeve is rotatably mounted on the mandrel by said cooperating bearing means comprising said outer surface of the mandrel and said elastomeric portion at the inner surface of the sleeve,

the upper part of said elastomeric portion providing a smooth band fitting closely all around said mandrel, said smooth band forming said detritus exclusion means.

9. Combination according to claim 1 wherein the outer periphery of the sleeve is provided with a plurality of longitudinally extending ribs circumferentially spaced apart, and the sleeve is rotatably mounted on the mandrel by said cooperating bearing means comprising said outer surface of the mandrel and said elastomeric portion at the inner surface of the sleeve, said elastomeric portion being provided with flutes extending longitudinally of the inner surface of the sleeve, said flutes extending from the lower end of said elastomeric portion upwardly past the mid portion of the elastomeric portion that lies half-way between the upper and lower ends thereof, said flutes terminating below the upper end of the elastomeric portion, said flutes providing relief of the fit between the mandrel and the elastomeric portion of the sleeve whereby detritus passing said detritus exclusion means can fall through said flutes out of said cooperating bearing means provided by said mandrel and elastomeric portion,

said detritus exclusion means including annular li-p means extending radially inwardly from the upper part of said elastomeric portion into sealing engagement with said mandrel.

References Cited by the Examiner UNITED STATES PATENTS 831,143 9/1906 Conrader 3084 913,286 2/1909 Heeter 166-84 1,496,698 6/ 1924 Wolfe 3084 1,775,403 9/1930 McLeod. 2,157,299 5/1939 Mercier 277-208 2,267,459 12/ 1941 Hait. 2,624,603 I/ 1953 Sweet 277-485 2,756,117 7/1956 Cotchett 308238 X 2,860,350 11/1958 Miller 3084 2,897,016 7/1959 Baker 3084 2,966,121 12/1960 Crowl 308238 X 3,063,759 11/1962 Moore 3084 3,076,683 2/1963 Hanley 30836.1 3,111,037 11/1963 Wallis 308238 X 3,197,262 7/ 1965 Fairchild 3084 3,218,087 11/1965 Hallesy 277188 X FOREIGN PATENTS 699,488 1l/1953 Great Britain.

MARTIN P. SCHWADRON, Primary Examiner. DAVID J. WILLIAMOWSKY, Examiner. L. L. JOHNSON, Assistant Examiner, 

1. APPARATUS FOR USE IN EARTH BORING INCLUDING IN COMBINATION WITH A TUBULAR STEEL MANDREL HAVING AN UPPER END AND A LOWER END AND HAVING A SLEEVE COAXIALLY MOUNTED THEREON AND STOP MEANS AT THE LOWER END OF THE MANDREL TO PREVENT DOWNWARD MOVEMENT OF THE SLEEVE RELATIVE TO THE MANDREL BEYOND SAID STOP MEANS, THE INNER SURFACE OF THE SLEEVE HAVING AN ELASTOMERIC PORTION, THE OUTER SURFACE OF THE MANDREL AND SAID ELASTOMERIC PORTION OF THE INNER SURFACE OF THE SLEEVE PROVIDING COOPERATING STEEL AND ELASTOMER BEARING MEANS CONSTRAINING THE RELATIVE MOTION OF THE MANDREL AND SLEEVE SUBSTANTIALLY TO SLIDING OF THE ELASTOMERIC PORTION OF THE INNER SURFACE OF THE SLEEVE UPON THE STEEL OUTER SURFACE OF THE MANDREL, THE IMPROVEMENT COMPRISING ELASTOMERIC DETRITUS EXCLUSION MEANS ON THE INNER SURFACE OF THE SLEEVE ADJACENT THE UPPER END OF THE ELASTOMERIC PORTION THEREOF COOPERATING WITH SAID MANDREL TO EXCLUDE DETRITUS OF LARGER SIZE THAN WILL PASS BETWEEN SAID COOPERATING BEARING MEANS, SAID DETRITUS EXCLUSION MEANS AND MANDREL MAKING A CLOSER FIT THAN SAID COOPERATING BEARING MEANS EXTENDING THEREBELOW FROM SAID UPPER END THROUGH THE MID PORTION OF SAID ELASTOMERIC PORTION TO THE LOWER END THEREOF, WHEREBY DETRITUS THAT CAN ENTER BETWEEN THE SLEEVE AND MANDREL AT THE UPPER END OF THE SLEEVE PAST SAID ELASTOMERIC EXCLUSION MEANS WILL BE OF A SIZE THAT CAN FALL THROUGH THE CLEARANCE SPACE BETWEEN SAID COOPERATING STEEL AND ELASTOMER BEARING MEANS AT THE OUTER SURFACE OF THE MANDREL AND INNER SURFACE OF THE SLEEVE WITHOUT SPOILING THE SLIDING FIT THEREBETWEEN. 